why does my Yamaha MO8 automatically copy the contents of one track to another track?

[Shawn Brown]

When recording a pattern my MO8 will automatically copy the contents of one track to another track. This usually happens when I either record to vocies of the same category or record the track out of order (I record on track 2 before I record on track one). EX: I record a drum voice on track one and another on track 2 when i play it back track 2 is exactly the same as track one.